Communication, biomedical, and radar systems often measure the amplitude and phase of an analog signal. For example, wireless transmitters and receivers that include beamforming arrays may measure the amplitude and phase of received signals in each RF device of the beamforming chain. Wireless devices such as base stations and access points, handheld devices such as phones and tablets, and personal computers may all need to measure the amplitude and phase of received signals. Such measurements typically require a high accuracy and are often performed in a small device or package.
Accurate measurements of a signal's amplitude and phase may be performed using vector network analyzers (VNAs). Such measurement systems may offer higher accuracy, but often require the use of analog-to-digital converters (ADCs), higher performance intermediate frequency (IF) sampling, and additional memory and digital signal processors (DSPs). Furthermore, VNAs may increase the cost and size of systems through the use of special RF boards and connectors, as well as the presence of an operator to perform the measurements.
Integrated analog systems that perform amplitude and phase detection have grown in popularity as technology has improved and the trend towards integration has continued. Analog systems have the potential to reduce device areas by having fewer components. However, traditionally, the accuracy of analog systems may be improved by increasing the size of components in the system, which may increase power consumption of the system. Increasing the size of components or the power consumption may increase the accuracy, but may increase chip area, reduce efficiency, or be encumbered by other technology constraints. Further, sometimes the device improvement may be insufficient to achieve the desired performance.